KR20220017139A - Optical system - Google Patents

Abstract

In accordance with an embodiment, an optical system includes an optical path changing member and a plurality of lenses sequentially placed along an optical axis in an upward direction from an object. The optical path changing member includes a reflector or prism, intervals between the plurality of lenses are invariable, and the uppermost lens of the plurality of lenses has an effective aperture larger than the other lenses. Moreover, in accordance with an embodiment, an optical system includes an optical path changing member, a plurality of lenses and an image sensor sequentially placed along an optical axis in an upward direction from an object. The optical path changing member includes a reflector or prism, and intervals between the plurality of lenses are invariable. When an optical axis distance from an upper side of a lens, which is the most adjacent to the image sensor, of the plurality of lenses to the image sensor is defined as a black focus length (BFL), and a 1/2 value of diagonal length of an effective area of the image sensor is defined as ImgH, 0.5 < ImgH / BFL < 1.5 can be satisfied. Therefore, the present invention is capable of improving an optical property in the design of a zoom lens.

Description

Optical system {OPTICAL SYSTEM}

Embodiments are directed to optics for improved optical performance.

The camera module captures an object and stores it as an image or video, and is installed in various applications. In particular, the camera module is produced in a very small size and is applied to not only portable devices such as smartphones, tablet PCs, and laptops, but also drones and vehicles to provide various functions.

For example, the optical system of the camera module may include an imaging lens that forms an image and an image sensor that converts the formed image into an electrical signal. In this case, the camera module may perform an autofocus (AF) function of aligning the focal lengths of the lenses by automatically adjusting the distance between the image sensor and the imaging lens, and a distant object through a zoom lens It is possible to perform a zooming function of zooming up or zooming out by increasing or decreasing the magnification of . In addition, the camera module employs image stabilization (IS) technology to correct or prevent image stabilization due to camera movement caused by an unstable fixing device or a user's movement.

The most important element for this camera module to obtain an image is an imaging lens that forms an image. Recently, interest in high performance such as high image quality and high resolution is increasing, and research on an optical system including a plurality of lenses is being conducted in order to realize this.

For example, research using a plurality of imaging lenses having positive (+) or negative (-) refractive power to implement a high-performance optical system is being conducted. However, when a plurality of lenses are included, the entire optical system may increase, and it is difficult to derive excellent optical and aberration characteristics.

In addition, when the Back Focus Length (BFL) in the optical system becomes longer, the light incident on the optical system is reflected on the inner surface of the device including the optical system, and a phenomenon such as a flare or a ghost may occur. can

Therefore, a new optical system capable of solving the above problems is required.

The embodiment is intended to provide an optical system with improved optical properties.

In addition, the embodiment intends to provide an optical system with improved telephoto performance.

An optical system according to an embodiment includes an optical path changing member and a plurality of lenses sequentially arranged along an optical axis from an object side to an image side, wherein the optical path changing member includes a reflector or a prism, The distance does not change, and the lens closest to the image side among the plurality of lenses has an effective aperture larger than that of the other lenses.

In addition, the plurality of lenses may include first to fifth lenses sequentially disposed along an optical axis from the object side to the image side direction.

In addition, the size of the effective aperture of each of the first lens and the fifth lens may satisfy Equation 1 below.

[Equation 1]

0.8 < CA11 / CA51 < 2

0.8 < CA12 / CA52 < 2

(In Equation 1, CA11 means the size of the effective aperture of the object-side surface of the first lens, and CA12 means the size of the effective aperture of the image-side surface of the first lens. Also, CA51 represents the size of the effective aperture of the image side of the first lens. It means the size of the effective aperture of the object side of the lens, and CA52 means the size of the effective aperture of the image side of the fifth lens.)

In addition, the size of the effective aperture of the first lens may be the largest among the sizes of the effective aperture of the first to fourth lenses.

In addition, when the optical axis direction distance from the image side of the fifth lens to the image sensor is defined as a back focus length (BFL), Equation 2 below may be satisfied.

[Equation 2]

0 < CA / BFL < 1

(In Equation 2, CA is the size of the effective aperture of the object-side surface or the image-side surface of one lens selected from among the first to fifth lenses.)

In addition, when the optical axis direction distance from the object-side surface of the first lens to the image sensor is defined as a total track length (TTL), Equation 3 below may be satisfied.

[Equation 3]

3 < TTL / BFL < 4.5

Also, the effective focal length (EFL) of the optical system may be greater than 10 mm.

Also, the optical system may have an F-number less than 3.8.

In addition, the chief ray incident angle (CRA) of the optical system may be less than 40.

Also, the first lens may have positive refractive power.

In addition, the fifth lens is an optical system having a positive refractive power.

In addition, the object-side surface of the third lens is an optical system having an inflection point.

In addition, the optical system according to the embodiment includes an optical path changing member, a plurality of lenses, and an image sensor sequentially arranged along an optical axis from the object side to the image side, wherein the optical path changing member includes a reflector or a prism, When the distance between the plurality of lenses does not change, and the optical axis direction distance from the image side of the lens closest to the image sensor among the plurality of lenses to the image sensor is defined as a back focus length (BFL), the following math Equation 4 can be satisfied.

[Equation 4]

0.5 < ImgH / BFL < 1.5

(In Equation 4, ImgH means a value of 1/2 of the diagonal length of the effective area of the image sensor.)

The optical system according to the embodiment may have improved optical properties. In detail, the optical system may include the plurality of lenses, and the effective aperture of the last lens closest to the image sensor may be larger than the effective aperture of the first lens closest to the object side. In particular, the effective aperture of the last lens may be the largest among the plurality of lenses, and accordingly, improved optical properties may be obtained when designing a zoom lens having image sensors of various sizes, such as small to large.

In addition, the optical system according to the embodiment may minimize or prevent occurrence of phenomena such as flare and ghost. In detail, the optical system may have a relatively small BFL (Back Focus Length) value. Accordingly, it is possible to minimize or prevent the light incident on the optical system from being reflected by the structure between the last lens and the image sensor. In addition, the optical system can easily correct a CRA (Chief Ray Angle) value, so that the optical system can have improved optical properties.

1 is a configuration diagram of an optical system according to an embodiment.
2 is a graph illustrating an aberration diagram of an optical system according to an embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, the technical spirit of the present invention is not limited to some of the described embodiments, but may be implemented in various different forms, and within the scope of the technical spirit of the present invention, one or more of the components may be selected between the embodiments. It can be used by combining or substituted with .

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be generally understood by those of ordinary skill in the art to which the present invention belongs, unless specifically defined and described explicitly. It may be interpreted as a meaning, and generally used terms such as terms defined in advance may be interpreted in consideration of the contextual meaning of the related art.

In addition, the terminology used in the embodiments of the present invention is for describing the embodiments and is not intended to limit the present invention. In this specification, the singular form may also include the plural form unless otherwise specified in the phrase, and when it is described as "at least one (or more than one) of A and (and) B, C", it is combined with A, B, C It may include one or more of all possible combinations.

In addition, in describing the components of the embodiment of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the component from other components, and are not limited to the essence, order, or order of the component by the term. And, when it is described that a component is 'connected', 'coupled' or 'connected' to another component, the component is not only directly connected, coupled or connected to the other component, but also with the component It may also include a case of 'connected', 'coupled' or 'connected' due to another element between the other elements.

In addition, when it is described as being formed or disposed on "above (above) or under (below)" of each component, top (above) or under (below) is one as well as when two components are in direct contact with each other. Also includes a case in which another component as described above is formed or disposed between two components. In addition, when expressed as "upper (upper) or lower (lower)", a meaning of not only an upper direction but also a lower direction based on one component may be included.

In addition, the convex surface of the lens may mean that the lens surface of the region corresponding to the optical axis has a convex shape, and the concave lens surface means that the lens surface of the region corresponding to the optical axis has a concave shape can do.

Also, "object-side surface" may mean a surface of the lens that faces the object side with respect to the optical axis, and "image-side surface" may mean a surface of the lens that faces the imaging surface with respect to the optical axis.

Also, the vertical direction may mean a direction perpendicular to the optical axis, and the end of the lens or the lens surface may mean the end of the effective area of the lens through which the incident light passes.

1 is a configuration diagram of an optical system according to an embodiment, and FIG. 2 is a graph illustrating an aberration diagram of an optical system according to an embodiment.

First, referring to FIG. 1 , the optical system 1000 according to the embodiment may include a plurality of lenses. For example, the optical system 1000 may include four or more lenses. In detail, the optical system 1000 may include five or more lenses.

The optical system 1000 includes a first lens 110 , a second lens 120 , a third lens 130 , a fourth lens 140 , and a fifth lens 150 sequentially arranged from the object side to the image side direction. ), a filter 500 and an image sensor 300 may be included. The first to fifth lenses 110 , 120 , 130 , 140 , and 150 may be sequentially disposed along the optical axis of the optical system 1000 .

The light corresponding to the image information of the object may sequentially pass through the first to fifth lenses 110 , 120 , 130 , 140 , and 150 to be incident on the image sensor 300 .

Also, the optical system 1000 may further include a light path changing member 50 .

The light path changing member 50 may change the path of the light by reflecting the light incident from the outside. The light path changing member 50 may include a reflector and a prism. For example, the light path changing member 50 may include a right-angle prism. When the light path changing member 50 includes a right-angle prism, the light path changing member 50 may change the path of the light by reflecting the path of the incident light at an angle of 90 degrees.

The light path changing member 50 may be disposed closer to the object side than the first to fifth lenses 110 , 120 , 130 , 140 , and 150 . That is, in the optical system 1000 , the optical path changing member 50 , the first lens 110 , the second lens 120 , and the third lens are sequentially disposed along the optical axis OA from the object side to the image side. 130 , a fourth lens 140 , a fifth lens 150 , a filter 500 , and an image sensor 300 may be included. The light path changing member 50 may change the path of the light in a set direction by reflecting the light incident from the outside. That is, the light path changing member 50 may change the path of the light incident on the light path changing member 50 toward the first to fifth lenses 110 , 120 , 130 , 140 , and 150 .

Each of the first to fifth lenses 110 , 120 , 130 , 140 , and 150 may include an effective area and an ineffective area. The effective area may be an area through which light incident on the lens passes. That is, the effective region may be a region in which incident light is refracted to realize optical properties.

The ineffective area may be disposed around the effective area. The ineffective area may be an area to which the light is not incident. That is, the ineffective region may be a region independent of the optical characteristic. Also, the ineffective region may be a region fixed to a barrel (not shown) for accommodating the lens.

The optical system 1000 according to the embodiment may include an aperture 200 for adjusting the amount of incident light. The aperture 200 may be disposed between two lenses selected from among the first to fifth lenses 110 , 120 , 130 , 140 and 150 . For example, the aperture 200 may be disposed between the first lens 110 and the second lens 120 .

In addition, at least one of the first to fifth lenses 110 , 120 , 130 , 140 and 150 may function as an aperture. For example, one lens surface selected from among the first to fifth lenses 110 , 120 , 130 , 140 , 150 may serve as an iris for controlling the amount of light incident on the optical system 1000 . .

The filter 500 may include at least one of an infrared filter and an optical filter such as a cover glass. The filter 500 may pass light of a set wavelength band and filter light of a different wavelength band. When the filter 500 includes an infrared filter, radiant heat emitted from external light may be blocked from being transmitted to the image sensor 300 . Also, the filter 500 may transmit visible light and reflect infrared light.

The image sensor 300 may detect light. In detail, the image sensor 300 may detect light that has sequentially passed through the first to fifth lenses 110 , 120 , 130 , 140 and 150 . The image sensor 300 may include a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS).

Hereinafter, the plurality of lenses will be described in detail.

The first lens 110 may have positive (+) refractive power. The first lens 110 may include a plastic or glass material. For example, the first lens 110 may be made of a plastic material.

The first lens 110 may include a first surface S1 defined as an object side surface and a second surface S2 defined as an image side surface. The first surface S1 may be convex, and the second surface S2 may be convex. That is, the first lens 110 may have a shape in which both surfaces are convex.

At least one of the first surface S1 and the second surface S2 may be an aspherical surface. For example, both the first surface S1 and the second surface S2 may be aspherical.

The second lens 120 may have negative (-) refractive power. The second lens 120 may include a plastic or glass material. For example, the second lens 120 may be made of a plastic material.

The second lens 120 may include a third surface S3 defined as an object side surface and a fourth surface S4 defined as an image side surface. The third surface S3 may be concave, and the fourth surface S4 may be convex. That is, the second lens 120 may have a meniscus shape convex toward the image.

At least one of the third surface S3 and the fourth surface S4 may be an aspherical surface. For example, both the third surface S3 and the fourth surface S4 may be aspherical.

The third lens 130 may have negative (-) refractive power. The third lens 130 may include a plastic or glass material. For example, the third lens 130 may be made of a plastic material.

The third lens 130 may include a fifth surface S5 defined as an object side surface and a sixth surface S6 defined as an image side surface. The fifth surface S5 may be concave, and the sixth surface S6 may be concave. That is, the third lens 130 may have a shape in which both surfaces are concave. Also, the third lens 130 may have an inflection point. In detail, an inflection point may be formed on the fifth surface S5 of the third lens 130 .

At least one of the fifth surface S5 and the sixth surface S6 may be an aspherical surface. For example, both the fifth surface S5 and the sixth surface S6 may be aspherical.

The fourth lens 140 may have positive (+) refractive power. The fourth lens 140 may include a plastic or glass material. For example, the fourth lens 140 may be made of a plastic material.

The fourth lens 140 may include a seventh surface S7 defined as an object side surface and an eighth surface S8 defined as an image side surface. The seventh surface S7 may be convex, and the eighth surface S8 may be concave. That is, the fourth lens 140 may have a meniscus shape convex toward the object.

At least one of the seventh surface S7 and the eighth surface S8 may be an aspherical surface. For example, both the seventh surface S7 and the eighth surface S8 may be aspherical.

The fifth lens 150 may have positive (+) refractive power. The fifth lens 150 may include a plastic or glass material. For example, the fifth lens 150 may be made of a plastic material.

The fifth lens 150 may include a ninth surface S9 defined as an object side surface and a tenth surface S10 defined as an image side surface. The ninth surface S9 may be convex, and the ninth surface S9 may be concave. That is, the fifth lens 150 may have a meniscus shape convex toward the object.

At least one of the ninth surface S9 and the tenth surface S10 may be an aspherical surface. For example, both the ninth surface S9 and the tenth surface S10 may be aspherical.

The first to fifth lenses 110 , 120 , 130 , 140 , and 150 may have a set clear aperture. For example, each of the first to tenth surfaces S1 , S2 , S3 , S4 , S5 , S6 , S7 , S8 , S9 , and S10 may have a set effective aperture.

In detail, among the first to fifth lenses 110 , 120 , 130 , 140 and 150 , the fifth lens 150 closest to the image sensor 300 includes the first to fourth lenses 110 , 120, 130, 140) may have an effective aperture larger. For example, the effective apertures of the ninth surface S9 and the tenth surface S10 of the fifth lens 150 are the first to eighth surfaces S1, S2, S3, S4, S5, S6, and S7. , S8) may have a larger effective aperture.

Also, the first lens 110 may have the largest effective aperture among the first to fourth lenses 110 , 120 , 130 , and 140 . For example, the effective apertures of the first surface S1 and the second surface S2 of the first lens 110 are those of the third to eighth surfaces S3, S4, S5, S6, S7, and S8. It may be larger than the effective aperture.

Also, the second lens 120 may have a larger effective aperture than the third lens 130 and the fourth lens 140 . For example, the effective apertures of the third and fourth surfaces S3 and S4 of the second lens 120 are the fifth to eighth surfaces S5 of the third and fourth lenses 130 and 140 . , S6, S7, S8) may be larger than the effective aperture.

Also, the effective aperture of the fourth lens 140 may be larger than the effective aperture of the third lens 130 . For example, the effective apertures of the seventh surface S7 and the eighth surface S8 of the fourth lens 140 are the fifth surface S5 and the sixth surface S6 of the third lens 130 . may be larger than the effective aperture of

Also, the optical system 1000 according to the embodiment may satisfy at least one of the following equations. Accordingly, when the optical system 1000 according to the embodiment satisfies at least one of the following equations, it may have improved optical properties.

[Equation 1]

0.8 < CA11 / CA51 < 2

0.8 < CA12 / CA52 < 2

In Equation 1, CA11 denotes the size of the effective aperture of the object-side surface (first surface S1) of the first lens 110, and CA12 denotes the image-side surface (second surface S1) of the first lens 110. It means the size of the effective aperture of the surface (S2)). In addition, CA51 denotes the size of the effective aperture of the object-side surface (the ninth surface S9) of the fifth lens 150, and CA52 denotes the image-side surface (the tenth surface (10th surface) of the fifth lens 150). It means the size of the effective aperture of S10)).

In detail, the effective aperture of the first lens 110 and the effective aperture of the fifth lens 150 may satisfy Equation 1-2 below.

[Equation 1-2]

0.8 < CA11 / CA51 < 1.8

0.8 < CA12 / CA52 < 1.8

In more detail, the effective aperture of the first lens 110 and the effective aperture of the fifth lens 150 may satisfy Equations 1-3 below.

[Equation 1-3]

0.8 < CA11 / CA51 < 1.5

0.8 < CA12 / CA52 < 1.5

[Equation 2]

0 < CA / BFL < 1

In Equation 2, CA means the size of the effective aperture of the object-side surface or the image-side surface of any one of the first to fifth lenses 110 , 120 , 130 , 140 , and 150 . In addition, the back focus length (BFL) refers to a distance in the optical axis direction from the image side surface (the tenth surface S10 ) of the fifth lens 150 to the image sensor 300 .

In detail, the effective aperture and BFL of the first to fifth lenses 110 , 120 , 130 , 140 and 150 may satisfy Equation 2-2 below.

[Equation 2-2]

0.3 < CA / BFL < 1

In more detail, the effective aperture and BFL of the first to fifth lenses 110 , 120 , 130 , 140 and 150 may satisfy Equation 2-3 below.

[Equation 2-3]

0.3 < CA / BFL < 0.8

[Equation 3]

3 < TTL / BFL < 5

In Equation 3, a total track length (TTL) means a distance in the optical axis direction from the object-side surface (the first surface S1 ) of the first lens 110 to the image sensor 300 .

[Equation 4]

0.5 < ImgH / BFL < 1.5

In Equation 4, ImgH means 1/2 of the diagonal length of the effective area of the image sensor 300 . That is, the ImgH denotes a vertical distance from the optical axis of the upper surface of the image sensor 300 to one field area.

In more detail, the ImgH and the BFL may satisfy Equation 4-2 below.

[Equation 4-2]

0.5 < ImgH / BFL < 1

[Equation 5]

EFL > 10mm

In Equation 5, EFL means an effective focal length of the optical system 1000 .

[Equation 6]

F-number < 3.8

In Equation 6, F-number means a numerical value representing the brightness of the optical system.

[Equation 7]

CRA < 40

In Equation 7, CRA (Chief Ray Angle) means an angle of light incident on the image sensor 300 .

[Equation 8]

2 < CT1/CT5 < 4

In Equation 8, CT1 denotes a central thickness of the first lens 110 , and CT5 denotes a central thickness of the fifth lens 150 .

[Equation 9]

|f5| > |f1|+|f2|+|f3|+|f4|

In Equation 9, f1 to f5 denote focal lengths of the first to fifth lenses 110 , 120 , 130 , 140 , and 150 , respectively.

[Equation 10]

20 < f5 / EFL < 50

In Equation 10, f5 denotes a focal length of the fifth lens 150 , and EFL denotes an effective focal length of the optical system 1000 .

[Equation 11]

In Equation 10, Z is Sag, which may mean a distance in the optical axis direction from an arbitrary position on the aspherical surface to the vertex of the aspherical surface.

In addition, Y may mean a distance in a direction perpendicular to the optical axis from an arbitrary position on the aspherical surface to the optical axis.

Also, c may mean a curvature of the lens, and K may mean a conic constant.

Also, A, B, C, D, ?? may mean an aspheric constant.

The optical system 1000 according to the embodiment may satisfy at least one of Equations 1 to 9. In this case, the optical system 1000 may have improved optical properties. In detail, when the optical system 1000 satisfies at least one of the above-described equations, a characteristic degradation phenomenon that occurs when the light incident on the optical system 1000 is reflected by a device accommodating the optical system 1000, for example, a flare It is possible to prevent a phenomenon such as flare or ghost from occurring.

lens noodle radius of curvature thickness or distance effective caliber refractive index Abbesu first lens side 1 4.043 1.5 1.55 1.5345 55.677 2nd side -8.1302 0.1324 1.4863638 second lens 3rd side -7.3286 1.5 1.416846 1.6397 23.262 side 4 -384.7888 0.8503 1.3826056 third lens page 5 17.482107 1.5 1.3135073 1.5345 55.677 page 6 3.8785 0.116989268 1.3031867 4th lens page 7 3.4444726 1.5 1.3192926 1.6397 23.262 page 8 3.2521355 0.667342341 1.3771759 5th lens page 9 6.2858121 0.5016011 1.5669996 1.5345 55.677 page 10 6.2822957 1.5378562

Item Example TTL 11.08676 F-number 3.4647 EFL 10.7407 BFL 2.818 ImgH 2.051 f1 5.256428 f2 -11.58088 f3 -9.65706 f4 43.734218 f5 428.46201

Table 1 shows the radius of curvature of the first to fifth lenses 110 , 120 , 130 , 140 , and 150 according to the embodiment, the thickness of each lens (mm) (thickness), and the distance (mm) (distance) between each lens ), refractive index, and Abbe's Number.

Referring to Table 1, refractive indices of the first lens 110 , the third lens 130 , and the fifth lens 150 may be the same, and the second lens 120 and the fourth lens The refractive indices of (140) may be equal to each other. In this case, the refractive indices of the first lens 110 , the third lens 130 , and the fifth lens 150 may be smaller than the refractive indices of the second lens 120 and the fourth lens 140 .

In addition, the Abbe numbers of the first lens 110 , the third lens 130 , and the fifth lens 150 may be the same, and the second lens 120 and the fourth lens 140 . may have the same Abbe numbers. In this case, the Abbe numbers of the first lens 110 , the third lens 130 , and the fifth lens 150 may be greater than the Abbe numbers of the second lens 120 and the fourth lens 140 . have.

In addition, Table 2 relates to the characteristics of the optical system 1000 according to the embodiment, and the total track length (TTL) of Table 2 is the vertex of the object-side surface (the first surface S1) of the first lens 110 . is the distance (mm) on the optical axis from to the upper surface of the image sensor 300 , and EFL (Effective Focal Length) is the optical system including the first to fifth lenses 110 , 120 , 130 , 140 , 150 . It may mean a focal length (mm) of (1000). And, the back focus length (BFL) may mean a distance (mm) in the optical axis direction from the image side surface (the tenth surface S10 ) of the fifth lens 150 to the image sensor 300 , f1 to Each of f5 may mean a focal length (mm) of each of the first to fifth lenses 110 , 120 , 130 , 140 and 150 . Referring to Table 2, the fifth lens 150 may have the largest focal length value among the first to fifth lenses 110 , 120 , 130 , 140 , and 150 .

In addition, the values of the aspheric coefficients of each lens in the optical system 1000 according to the embodiment are shown in Table 3.

K A B C D E F G H J side 1 -4.624774 -0.226312E-02 0.489390E-02 -0.509701E-02 0.217648E-02 -0.566567E-03 0.558957E-04 0.000000E+00 0.000000E+00 0.00000E+00 2nd side 0.000000 -0.419606E-01 0.604368E-01 -0.470338E-01 0.138559E-01 0.375169E-03 -0.122076E-02 0.278259E-03 -0.204382E-04 0.000000E+00 3rd side -7.463160 -0.232627E-01 0.527822E-01 -0.444088E-01 0.151247E-01 -0.146984E-02 -0.296560E-03 0.625074E-04 0.000000E+00 0.00000E+00 side 4 -99.00000 0.119356E-02 0.445158E-0 -0.108605E-01 0.641443E-02 -0.599468E-03 -0.179139E-02 0.109799E-02 -0.196984E-03 0.000000E+00
page 5 -99.00000 0.214541E-02 -0.365989E-01 0.624896E-01 -0. 628915E-01 0.298347E-01 -0. 531098E-02 0.000000E+00 0.000000E+00 0.000000E+00 page 6 -44.256666 0.637372E-01 -0. 995684E-01 0.171046E+00 -0. 906703E-01 -0. 160399E+00 0.293791E+00 -0. 198733E+00 0.636119E-01 -0. 805047E-02 page 7 -99.00000 0.114492E+00 -0. 318890E+00 0.628853E+00 -0. 788570E+00 0.602565E+00 -0. 270609E+00 0.651563E-01 -0. 643303E-02 0.000000E+00 page 8 0.684650 -0.230664E-01 -0.204520E-01 0.756834E-01 -0. 120926E+00 0.106326E+00 -0.524879E-01 0.135195E-01 -0. 139956E-02 0.000000E+00 page 9 0.000000 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 page 10 0.000000 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00

formula Example Equation 1 0.8 < CA11 / CA51 < 2
0.8 < CA12 / CA52 < 2 CA11 / CA51 = 0.989
CA12 / CA52 = 0.966 Equation 2 0 < CA / BFL < 1 All of the 1st to 5th lenses are satisfied Equation 3 3 < TTL / BFL < 5 TTL/BFL = 3.93 Equation 4 0.5 < ImgH / BFL < 1.5 ImgH/BFL = 0.727 Equation 5 EFL > 10mm satisfied Equation 6 F-number < 3.8 satisfied Equation 7 CRA < 40 < 40 Equation 8 2 < CT1/CT5 < 4 CT1/CT5 = 2.99 Equation 9 |f5| > |f1|+|f2|+|f3|+|f4| 428.462 > 80.969 Equation 10 20 < f5 / EFL < 50 f5 / EFL = 39.891

Table 4 shows the values of the optical system 1000 for the above-described equations.

Referring to Table 4, it can be seen that the optical system 1000 according to the embodiment satisfies at least one of Equations 1 to 9. In detail, it can be seen that the optical system 1000 satisfies all of Equations 1 to 10.

Accordingly, the optical system 1000 according to the embodiment may have an aberration characteristic as shown in FIG. 2 . In detail, FIG. 2 is a graph showing an aberration diagram of the optical system 1000 according to the embodiment, in which Longitudinal Spherical Aberration, Astigmatic Field Curves, and Distortion are measured from left to right. It is a graph. In FIG. 2 , the X-axis may indicate a focal length (mm) and distortion (%), and the Y-axis may indicate the height of an image. In addition, the graph for spherical aberration is a graph for light in the wavelength bands of 435 nm, 486 nm, 546 nm, 587 nm, and 656.3 nm, and the graph for astigmatism and distortion aberration is a graph for light in the 546 nm wavelength band.

That is, the optical system 1000 according to the embodiment may have improved optical properties. In detail, in the optical system 1000, the effective aperture of the fifth lens 150 closest to the image sensor 300 is larger than the effective aperture of the first lens 110 closest to the object side, thereby improving optical properties. can have In particular, as the effective aperture of the fifth lens 150 is the largest among the plurality of lenses, it is possible to have improved optical characteristics when designing a zoom lens having the image sensor 300 of various sizes, such as small to large. In addition, when the optical system 1000 is applied as a telephoto lens, improved optical properties may be obtained.

In addition, the optical system may have improved optical properties by having a relatively small back focus length (BFL) value. In detail, as the distance BFL between the image sensor 300 and the fifth lens 150 has a relatively small value, the light incident on the optical system 1000 is separated from the fifth lens 150 and the fifth lens 150 . Reflection of the structure between the image sensors 300 may be prevented or minimized. Accordingly, the optical system 1000 according to the embodiment may have improved optical properties by easily correcting a CRA value, for example, an angle of light passing through the fifth lens 150 and incident on the image sensor 300 .

Features, structures, effects, etc. described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, features, structures, effects, etc. illustrated in each embodiment can be combined or modified for other embodiments by those of ordinary skill in the art to which the embodiments belong. Accordingly, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention.

In addition, although the embodiment has been described above, it is only an example and does not limit the present invention, and those of ordinary skill in the art to which the present invention pertains are exemplified above in a range that does not depart from the essential characteristics of the present embodiment. It can be seen that various modifications and applications that have not been made are possible. For example, each component specifically shown in the embodiment can be implemented by modification. And differences related to such modifications and applications should be construed as being included in the scope of the present invention defined in the appended claims.

Optical system: 1000 Light path change member: 50
First lens: 110 Second lens: 120
Third lens: 130 Fourth lens: 140
5th lens: 150 Image sensor: 500

Claims (13)

It includes an optical path changing member and a plurality of lenses sequentially arranged along the optical axis from the object side to the image side,
The light path changing member includes a reflector or a prism,
The distance between the plurality of lenses does not change,
An optical system in which a lens closest to the image side among the plurality of lenses has an effective aperture larger than that of the remaining lenses. According to claim 1,
The plurality of lenses,
and first to fifth lenses sequentially arranged along an optical axis from the object side to the image side direction. 3. The method of claim 2,
The size of the effective aperture of each of the first lens and the fifth lens satisfies Equation 1 below.
[Equation 1]
0.8 < CA11 / CA51 < 2
0.8 < CA12 / CA52 < 2
(In Equation 1, CA11 means the size of the effective aperture of the object-side surface of the first lens, and CA12 means the size of the effective aperture of the image-side surface of the first lens. Also, CA51 represents the size of the effective aperture of the image side of the first lens. It means the size of the effective aperture of the object side of the lens, and CA52 means the size of the effective aperture of the image side of the fifth lens.) 4. The method of claim 3,
The size of the effective aperture of the first lens is the largest among the sizes of the effective apertures of the first to fourth lenses. 4. The method of claim 3,
When the optical axis direction distance from the image side of the fifth lens to the image sensor is defined as a back focus length (BFL), an optical system satisfying Equation 2 below.
[Equation 2]
0 < CA / BFL < 1
(In Equation 2, CA is the size of the effective aperture of the object-side surface or the image-side surface of one lens selected from among the first to fifth lenses.) 6. The method of claim 5,
When the optical axis direction distance from the object side surface of the first lens to the image sensor is defined as a total track length (TTL), an optical system satisfying Equation 3 below.
[Equation 3]
3 < TTL / BFL < 4.5 3. The method of claim 2,
An effective focal length (EFL) of the optical system is greater than 10 mm. 3. The method of claim 2,
The optical system has an F-number less than 3.8. 3. The method of claim 2,
A chief ray incidence angle (CRA) of the optical system is less than 40. 3. The method of claim 2,
The first lens is an optical system having a positive refractive power. 3. The method of claim 2,
The fifth lens is an optical system having a positive refractive power. 3. The method of claim 2,
The object-side surface of the third lens is an optical system having an inflection point. an optical path changing member sequentially arranged along an optical axis from an object side to an image side direction, a plurality of lenses; and
an image sensor;
The light path changing member includes a reflector or a prism,
The distance between the plurality of lenses does not change,
When the optical axis direction distance from the image side of the lens closest to the image sensor among the plurality of lenses to the image sensor is defined as a back focus length (BFL), an optical system satisfying Equation 4 below.
[Equation 4]
0.5 < ImgH / BFL < 1.5
(In Equation 4, ImgH means 1/2 of the diagonal length of the effective area of the image sensor.)

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